System and method for pump-controlled cylinder cushioning

a hydraulic actuator and pump-controlled technology, applied in the direction of fluid couplings, rotary clutches, servomotors, etc., can solve the problems of stroke, throttling flow through control valves, waste of energy,

Active Publication Date: 2010-05-13
PURDUE RES FOUND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0006]The present invention provides a system and method for cushioning pump-controlled hydraulic actuators that do not require the use of a fluid component such as a viscous damper. ...

Problems solved by technology

However, throttling flow through control valves is known to waste energy.
Hydraulic actuators have a limited position range, or stroke.
Without some form of cushioning, the impact between the piston and cylinder can cause undesir...

Method used

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  • System and method for pump-controlled cylinder cushioning
  • System and method for pump-controlled cylinder cushioning
  • System and method for pump-controlled cylinder cushioning

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Embodiment Construction

[0014]FIG. 2 schematically represents a system 10 for automatically controlling the position and velocity of a pump-controlled hydraulic actuator 12. The system 10 is represented in FIG. 2 as comprising a closed hydraulic circuit containing a pump-controlled hydraulic actuator 12 adapted to control the movement of an implement of an earthmoving machine, nonlimiting examples being any of the implements 104-108 of the excavator 100 of FIG. 1. As such, the actuator 12 can be exemplified by any of the linear actuators 109-114 of the excavator 100.

[0015]The system 10 of FIG. 2 further includes a variable displacement pump 14 connected to the hydraulic actuator 12, represented as a single-rod double-acting actuator. The pump 14 is powered by a primary power source (not shown), for example, an internal combustion engine. One or more valves 18 connect the hydraulic circuit to a suitable hydraulic fluid source, such as a charge pump 20 and reservoir 30 shown in FIG. 2, though the use of othe...

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Abstract

A system and method for controlling the movement of an implement of an earthmoving machine. The system includes a hydraulic actuator adapted to move the implement. A variable displacement pump is coupled to the actuator for delivering a pressurized fluid to and receiving pressurized fluid from chambers within the actuator. A sensor generates an output based on the position of the actuator's piston or piston rod, and a controller controls the displacement of the variable displacement pump in response to the output of the sensor by executing an algorithm to reduce the flow rate of the fluid to and from the actuator's chambers and thereby reduce the velocity of the piston as it approaches an end of a piston stroke thereof and prevent the piston from impacting the actuator at the end of the piston stroke.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 111,748, filed Nov. 6, 2008, the contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]The present invention generally relates to systems for operating hydraulic circuits. More particularly, this invention relates to a system and method for pump-controlled cushioning of a hydraulic actuator used to control the position of a working implement on a mobile machine.[0003]Compact excavators, wheel loaders and skid-steer loaders are examples of multi-function machines whose operations involve controlling movements of various implements of the machines. FIG. 1 illustrates a compact excavator 100 as having a cab 101 mounted on top of an undercarriage 102 via a swing bearing (not shown) or other suitable device. The undercarriage 102 includes tracks 103 and associated drive components, such as drive sprockets, rollers, idlers, etc. The exca...

Claims

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Application Information

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IPC IPC(8): F15B9/04
CPCE02F9/2207E02F9/2228F15B11/048F15B21/08F15B2211/20546F15B2211/20561F15B2211/27F15B2211/6336F15B2211/785E02F9/2214E02F9/2289E02F9/22F15B11/02E02F3/43
Inventor WILLIAMSON, CHRISTOPHER ALANIVANTYSYNOVA, MONIKA MARIANNE
Owner PURDUE RES FOUND INC
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